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- Andersson, Linus, et al.
(författare)
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Reduced order modeling for the dynamic analysis of structures with nonlinear interfaces
- 2019
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Ingår i: COMPDYN 2019 - 7th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering, Proceedings. - 2623-3347. - 9786188284470 ; 2, s. 2395-2406
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Konferensbidrag (refereegranskat)abstract
- In the present paper, linear substructures with nonlinearities localized at their interfaces, such as the joints in a beam structure, are studied. By subdivision of the total structure into substructures, reduced subsystems are obtained by component mode synthesis. Nonlinear elements are introduced at supports or between substructures. A numerical example is presented where a beam subjected to blast loading is studied. The influence of the nonlinear behavior as well as the number of retained fixed-interface normal modes in the reduced subsystems are evaluated. The response is also compared to the response of equivalent single-degree-of-freedom systems, which are frequently employed in blast load design calculations. For the load cases studied, the displacement computed from an equivalent single-degree-of-freedom system correspond fairly well to the displacement given by a refined two-dimensional beam model, reduced by substructuring. In contrast, the shear force differs significantly due to that higher order modes are neglected in the single-degree-of-freedom system.
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- Andersson, Linus, et al.
(författare)
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Reduced order modeling of soft-body impact on glass panels
- 2022
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Ingår i: Engineering Structures. - : Elsevier BV. - 0141-0296. ; 256
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Tidskriftsartikel (refereegranskat)abstract
- In the paper, strategies for reduced order modeling of glass panels subjected to soft-body impact are developed by means of dynamic substructuring. The aim is to obtain accurate and computationally efficient models for prediction of the pre-failure elastic response. More specifically, a reduction basis for the subsystem representing the glass panel is established using correction modes, being fixed-interface component modes that considers loading on the substructure boundary. The soft-body impactor is effectively modeled by a nonlinear single-degree-of-freedom system, calibrated by experimental data. Furthermore, a simplified and computationally efficient modeling approach is proposed for the contact interaction between the glass panel and the impact body. An experimental campaign was carried out to validate the developed models. In particular, the glass strain was measured on simply supported monolithic glass panels subjected to soft-body impact. Additional impact tests were performed to determine the dynamic characteristics of the impactor. Moreover, a detailed numerical reference model was developed to evaluate the discrepancy between the experimental tests and the results provided by the reduced order models. The developed models show good agreement with the experimental results. For the studied load cases, it is shown that an accurate prediction of the pre-failure glass strain can be obtained by systems including only a few generalized degrees-of-freedom.
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- Austrell, Per Erik, et al.
(författare)
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A viscoelastic bump stop model for multi-body simulations based on impact test data
- 2008
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Ingår i: Constitutive Models for Rubber V. ; , s. 393-398
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Konferensbidrag (refereegranskat)abstract
- The studied bump stop is a hollow folded polyurethane cylinder mounted around the damper rod in a MacPherson front wheel suspension, restricting the upward wheel displacement. It is a critical component for durability since the force transfer through the bump stop determines the vertical peak loads to the car body. In extreme load cases as driving over a curb, the bump stop is subjected to impact loading giving a highly non-linear behavior. The nominal compressive strain can reach 80% under a load duration of milliseconds. The presented model is based on impact test data. By performing drop tests, high load levels and short contact times can be combined, giving a realistic loading in view of road load data from the test track. The main objective of the model is to predict the behavior at high strain rates and strain levels. The strongly progressive behavior, shown in a stress strain diagram, both in terms of the loading curve and the hysteresis, requires special attention. The main feature of the model is a linear viscoelastic Maxwell model combined with a function that takes care of the strongly progressive behavior. This function, obtained from a dynamic loading curve in the impact test, is multiplied with the Maxwell stress, giving the sought progressive behavior. The model is accurate, simple to obtain from the impact test, computationally efficient, and easy to implement in commercial multi-body-system codes as ADAMS and can thus successfully be used in the product development of new cars.
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- Austrell, Per Erik
(författare)
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Analytical modelling of hysteresis heating in rolling contact of rubber covered rollers
- 2013
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Ingår i: Plastics, Rubber and Composites. - 1465-8011. ; 42:7, s. 276-281
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Tidskriftsartikel (refereegranskat)abstract
- In a previous paper, an approximate model for the contact between a rubber covered roller and a rigid roller was developed as analytical functional relationships connecting geometric parameters and material properties of the rubber to nip properties such as maximum contact pressure, etc. in a two-dimensional relationship. The results from that development are used in this work, with the objective to provide a means of estimating the temperature rise due to hysteresis heating. In the heat conduction modelling, one-dimensional steady state heat conduction is assumed. The heat source is a power input coming from internal friction developed during the rolling contact. The power input is expressed by the hysteresis in the rubber represented by a loss angle of the material together with the peripheral speed and some parameters taken from the previously developed contact model. The temperature distribution is calculated in accordance with temperature and heat flow boundary conditions.
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- Austrell, Per Erik, et al.
(författare)
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Considering amplitude dependence during cyclic loading of elastomers using an equivalent viscoelastic approach
- 2012
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Ingår i: Polymer Testing. - : Elsevier BV. - 0142-9418. ; 31:7, s. 909-915
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Tidskriftsartikel (refereegranskat)abstract
- Although it is well known that the dynamic properties of rubber depend on both frequency and amplitude, there are few commercially available finite element codes that take account of these effects. This paper outlines a simplified procedure to extend the usability of the commercially available frequency dependent viscoelastic finite element models to also take account of the amplitude dependence. By first calculating the load level at each element it is possible to obtain an equivalent viscoelastic model for a cyclic load. Using this approach, two different frequency dependent models are treated; one frequency and one time domain viscoelastic model. Both models are verified against experimental data with good results. (c) 2012 Elsevier Ltd. All rights reserved.
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- Austrell, Per Erik, et al.
(författare)
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Development of an extremely fatigue-resistant Shock Absorber
- 2014
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Ingår i: Kgk: Kautschuk Gummi Kunststoffe. - 0948-3276. ; 67:11-12, s. 24-31
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Tidskriftsartikel (refereegranskat)abstract
- An extremely fatigue resistant shock absorber was developed from basic mechanics principles using nonlinear elastic material models and finite element analysis. Prototypes were manufactured and tested to confirm the calculations and to find out the fatigue properties. The rubber body fills a cavity at gradually increasing compression. This idea has some clear advantages: A large part of the rubber body is protected against accidental external influences and it is backed up during the deformation by the cavity walls. Also, the stress in the rubber body becomes evenly distributed as only compressive stress is developed in it. The prototypes were tested in nearly 6 million cycles with no visible defects.
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